The present invention relates to optical scanning devices and more specifically to an automatic sensing and programming circuit and a programming method for optical scanners.
Optical scanners are well known for their usefulness in retail checkout and inventory control. They may be mounted within checkout counters, free-standing, or hand-held.
Optical scanners may also be programmable. Tags containing program information encoded into bar code labels may be used to program a scanner. Known programming methods employ one function per tag. While this method works well, the total number of tags becomes unmanageable as more functions are added.
One scanner may be used to program another. The receiving scanner detects the laser beam emitted from the emitting scanner. While this method works well, diffuser plates must be employed between the emitter and the receiver. Furthermore, the scanners must be configured in a non-scanning mode, a mode which is not certifiable as complying with safety regulations.
Optical scanners employ a variety of energizing devices. Some use triggers or other types of switches, while others use presence sensors, such as ambient light sensors and motion sensors. Energizing devices are often used in combination with a timing circuit for deenergizing the scanner after a predetermined time period.
While these energizing devices work well, they may require preparatory movements by the operator, separate from scanning movements, to energize the scanner. When presence sensors are employed, they may be mounted on the exterior of the scanner, or the volume covered by such sensors may not be coextensive with the scanning volume. Finally, the presence sensors have not been used to program, or receive programming instructions from, other scanners.
Therefore, it would be desirable to add a presence sensing circuit to an optical scanner which employs internal sensors, which can also be used to program other scanners, and whose sensing volume is coextensive with the scanning volume.